👉 Infection is a process by which a pathogen, such as a virus or bacterium, enters and takes control of a host cell, disrupting its normal functions and leading to disease. When a pathogen invades, it can replicate rapidly, overwhelming the host's immune system and causing harm. This invasion often begins with the pathogen attaching to specific receptors on the host cell surface, then either entering through endocytosis or directly fusing with the cell membrane. Once inside, the pathogen may hijack cellular machinery to produce more copies of itself, spread to other cells, or evade the immune response. Symptoms of infection arise as the body's defenses struggle to contain the invaders, ranging from mild discomfort to severe illness. Effective treatment and prevention rely on understanding how pathogens infect and replicate within hosts, aiming to either block entry, enhance immune responses, or directly target and eliminate the invading agents.
